Enhancement of electrical performance in In2O3 thin-film transistors by improving the densification and surface morphology of channel layers

We report on the fabrication of bottom-gate thin-film transistors (TFTs) using indium-oxide (In2O3) thin films as active channel layers. The films were deposited on thermally grown silicon dioxide (SiO2)/n-type silicon (Si) at room temperature (RT) by radio-frequency (RF) magnetron sputtering. The effect of deposition pressure on the performance of In2O3-TFTs was investigated in detail. A significant improvement of the device performance was observed for In2O3-TFTs with the decrease of the working pressure, which is attributed to enhanced densification, better surface morphology of the In2O3 channel layers prepared at lower deposition pressure. The fabricated TFT with optimal device performance exhibited a field-effect mobility (μFE) of 31.6 cm2 V−1 s−1, a drain current on/off ratio of ∼107, a low off drain current of about 10−10 A and a threshold voltage of 7.8 V. Good device performance and low processing temperature make the In2O3-TFTs suitable for the potential applications in the transparent electronics.